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(NO Model.) 2 SheBtSSheet J. J. MGNALLY. TELEPHONE SYSTEM.

No. 511,739. Patented De'c.'26,f1893.

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JOHN J. MCNALLY, OF CALIFORNIA, MISSOURI.

TELEPHONE SYSTEM..

SPECIFICATION forming part of Letters Patent No. 511,739, dated December 26, 1893,

Applicationiled August 31, 1893. Serial No. 484,504. (No model.)

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Be it known that I, JOHN J. MCNALLY, a citizen of the United States, residing at California, in the county of Moniteau and State of Missouri, have invented certain new and useful Improvementsin Systems of and Apparatus for Operating Telephone and Telegraph Lines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in systems of and apparatus for operating telephone and telegraph lines, and it has for its object to automatically make the connections between one station and another.

The invention will first be described in connection with the accompanying` drawings, and then particularly pointed out in the claim.

In the drawings--Figure 1 is a diagrammatic View of a system with two offices embodying my invention. Fig. 2 is a front elevation of the mechanism which is used for each office. Fig. 3 is a central vertical section of the indicator. Fig. 4 is a side view illustrating the construction of the local switch.

Referring to the drawings, A is a central station, while B, and O are offices. These ofces are connected to each other through the two main circuits E and F, one of which, (E) I will designate the indicator circuit, while the other (F) is the. instrument circuit, the term instrument referring to either a telephone, telegraph or other similar device.

Gr is a main battery serving to energize both circuits and connected as shown.

In each station or office is located an indicater l, a telephone or telegraph instrument 2, a bell call 3, a circuit-breaker i, an electromagnetic switch 5, a local circuit in which the bell is included, and a local battery for energizing the local circuit.

In the central office is an electro-magnetic switch which closes the indicator circuit when its magnets are energized, and Y opens the Same circuit when its magnets are de-energized. l

The operation, broadly considered, is as follows: The indicator circuit is normally open, while the instrument circuit is normally closed. Any office desiring to call another office opens the instrument circuit which demagnetizes the main electro magnetic switchY in the central oflice, thereby closing the indicator circuit. The indicators in all the oftices are included in this indicator circuit and each indicator is provided with an electromagnetic stepfby-step mechanism which rotates its respective indicators, this mechanism being operated by the making and breaking of the indicator circuit through the medium of the circuit breaker in the office which does the calling. The indicators move synchronously step-by-step, at each step indicating a number on a dial, as will be more fully explained hereinafter. Then the indicator in the calling office points to the number of the office which it is desired to call, the indicator hand will come in contact with a plug stuck in a perforation in the tace of the dial opposite the number of the station called, by which act the instrument circuit is automatically closed, which energizes the main electro magnetic switch in the central office and thereby opens the indicator circuit. At the same time, a local electro magnetic switch in each oce is energized, but these switches have an abortive function in every ofiice except that whose number is shown on the indicator. In the last mentioned office the local electro-magnetic switch closes a local circuit which rings the call bell and indicates to the oflice that it is called. The telephones or other instruments of both the office calling and the office called may then be switched onto the instrument circuit in the usual way.

The indicator is constructed. as follows: On a revoluble axis G is fixed a front anda back indicator needle or hand 7 and S the front one moving over a front dial 9, while the rear one moves over a rear dial 10. Between the back indicator hand and the front dial is a ratchet-Wheel 1l also fixed to the axis. This ratchetwheel is moved by a pawlrod 12, moving in guides 13 and provided with a pawl or tooth 14 which engages the teeth of the ratchet-wheel. The upper end of the pawl-rod is pivotally attached to one end of a lever 15, pivoted at t 1G, and carrying an armature 17, adapted to be drawn down by electro-magnets 18, which are included in the indicator circuit. The down- IOO ` wouldl be directly below the number 3 on the ward movement of the armature of course also draws down the lever'and the pawl-rod, and to raise them again a spring 19 is provided, being attached at one end to an arm 2O projecting downward from the lever and at the other end to a post 2l. The tension of the spring is adjustable :in a well-known manner by means of a screw 22 and nut 23. The play of the lever is also adjustable by means of screws 24 and 25 as will be fully understood from the drawings.

It is plain that as the indicator circuit is made and broken, the electro-magnets will draw the lever and pawl-rod down, while the spring will force it up, thereby rotating the ratchet-wheel one tooth each time, and as numbers on the front dial correspond to the teeth onthe ratchet-Wheel, the front indicator hand will move over the front dial one number ata time. To prevent the momentum of the rotating ratchet-wheel from carrying it too far, a leaf spring. 26 is secured to thedial and bears against a flange 27 formed integral with the ratchet-wheel and having flattened surfaces as shown at 28.

i To interrupt the indicatorcircuit and thereby actuate the step-by-step mechanism, a circuit-breaker is provided in each oliice, as before stated, this consisting, preferably, of a gear-wheel 29 rotated by a pinion 30 and crank 3l".V To vone side of the gear-wheel and preferablyintegral therewith is a cam-disk 32 provided with a series of cams 33, which are arranged to engage the end of a spring 34 and force it away from a contact point 35, the contactpoint and the spring beingA included in the indicator circuit.

Itis vplain that by turning the crank 3l the circuit will be opened and closed the spring 34 normallyresting against the contact point 35.

On' the back dial of each indicator are located two studs or posts 36 and 37 included inl the instrument circuit, as shown,Fig. l, the position of these studs onvthe back dial being differentfor each indicator on the line. For instance, in :an office to which, saythe number 3 was assigned, the studs or posts frontdial, while office number 4 would have the v`studs below the number 4 of the front dial, dac. One ofthe studsv 36 is connected by la wire `33 to one pole 39 of a plug cut-out, the other pole 40, of which is connected by a wire 41l to the other. stud, 37, and'pole 39 is` also connected to the front indicator hand, as will be rfully understood lfrom the drawings. A telephone or telegraph instrument 2 isineluded in the branch circuit formed bywire 41'. Y The front dial is provided with a series of holes correspondinglto thenumbers on the dial and adapted to receive a plugv 42 which is normally located in the plug-opening between the two poles 39 and 40 of the plugcut-out and serves to make a connection between such poles.r This pjlugis connected by a liexible wire to the pole 40 of thecutlout, S0 that when placed in any desired hole ot each other and from the lever. or points are included in a local circuit 46 in which a call bell 47 and a local battery 48 are has been opened by the removal of such plug from the cut-out. Immediately opposite the two studs 36 and 37 is placed an electro-magneticl switch included in the instrument circuit and constructed similar to an ordinary telegraph sounder, being provided at the end of its armature lever 43, with a pair of teeth or contact points, 44 and 45, insulated from These teeth included. The end of the armature lever of this local circuit switch isotsuch size that it will enter snugly betweeny the twoA studs' 36 and 37 and will mak-e acontact between'them. To prevent this taking place when not.Y desired, an insulating plug 49r as'seen in Fig. 4 is arranged to be insertedin the space!4 between such studs 36 and 37by the office calling. It is plain that when the local circuit switch is magnetized by the closing'ot the instrument circuit itwill have its lever'draw-n down between the studs 36 and37 andlwill then cut out the telephone of its own'ottice. But the office calling,having already inserted the insulating? plug 49'between thevtwo 'stu ds will not have its telephone cutfoutifandthe rear indicatorneedle orfhand of thefoft'ice called will then bedirectlyfover'the twostuds of the indicator, `and consequently itstelephone cannot lbe cutout byl itsrlocal-i switch. As soon as thelocal switch, of theoft'ice called, is magneti-Zed bythe closingr of thevinstru- `ment circuit at the cal-ling! oftice.(w`hich,- as

before stated, is done by the front indicator needle striking theplugv resti-ngA in the. hole opposite the number of the oiiice to be called) the contact points 44 and 45 are connected by contacting with the metallic rear khan'dof the indicator and the local circuit at thefoftice called is thereby closed, thus ringing thezc'allbell. A suitable switch 50 placed convenient to the telephone permits the'operator atthe office called `to cut out his: bell temporarily, and this switch may either be. operated-V by the hanging up or removing of the receiver of the telephone or by a spring push-buttonv so that it will be impossible for the operator to leave the callbell cutout by-accident.

The electro-magnetic switchin the central office is constructed similar to an ordinary telegraph sounder, and is provided ati the end of its armature lever with a tapered plugY 51 `which enters the opening between they two `poles 52 and 53 of a plugcut-.outincluded in gthe indicator circuit. A spring-54fserves-to draw the armature-lever upward so as to closethevindicator circuit, `while the energizling of the electro-magnetsdraws-the lever down and yholds it'down so long-as the instrument circuit is closed. f

position opposite the number of the office to which he has been talking and places the said plug in the hole opposite zero; by then turning the crank of the circuit-breaker, the indicators are all moved around to zero. The plug 42 is then removed from the hole at zero and inserted in its normal place between the poles 39 and 40 of the cutout. A solid plug is then placed in the hole at zero in contact with the front indicator hand.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-

In a system for operating telephones and similar instruments, the combination with a normally open indicator circuit, a normally closed instrument circuit, means for energizing both circuits, an electro-magnetic switch and included in the instrument circuit, aplug connected to one ofthe poles of the cut-out and insertible in the front dial in the path of thefront needle, a wi re connecting the other pole of the cut-outto the front needle, a pair of studs included in the instrument circuit, a local electro-magnetic switch included in the instrument circuit, and provided with a lever arranged to connect the two studs, and with two contact points arranged to engage the back needle of the indicator when the latter is 1n line with the lever, a local circuit ending at the contact points on the lever, a bell included in the local circuit, means for energizing the local circuit, and a series of telephones included in the instrument circuit and arranged to be cut out by the entry of the lever of the local switch between the two studs, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

JOHN J. MONALLY. Vitnesses:

J AMES E. HAZELL, THOMAS J. BUCHANAN. 

